Jiang T, Dong Z, Ma C, Wang Y. Toward Perception-Based Shape Decomposition, in The 11th Asian Conference on Computer Vision, ACCV 2012, November 5-9, 2012.Vol 7725. Daejeon, Korea: Springer; 2012:188–201. 访问链接
[1] Fine particles (PM2.5) were collected using filter-based high-volume samplers during summer-winter 2008 at a rural site in the central Pearl River Delta (PRD), south China, to determine typical secondary organic aerosol (SOA) tracers from significant biogenic (isoprene, monoterpenes, and sesquiterpenes) and anthropogenic (aromatics) precursors. Average isoprene SOA tracers were significantly higher during summer (126 ng m−3) than during fall-winter (25.1 ng m−3), owing largely to the higher isoprene emission and reaction rates in summer. Average monoterpene SOA tracers during summer (11.6 ng m−3) and fall-winter (16.4 ng m−3) showed much less difference compared to isoprene SOA tracers, probably resulting from the counteracting effects of temperature on the precursor emission/tracer formation and on gas/particle partitioning. The concentrations of the aromatics' SOA tracer (2,3-dihydroxy-4-oxopentanoic acid) ranged from 1.70 to 52.0 ng m−3 with an average of 15.1 ng m−3, which was the highest reported in ambient air. The secondary organic carbon (SOC) estimated by the SOA-tracer method averaged 3.07 μg C m−3 in summer and 2.00 μg C m−3 in fall-winter, contributing 38.4% and 8.7% to OC, respectively. During summer, aromatics-SOC and isoprene-SOC reached 2.25 ± 1.5 μg C m−3 and 0.64 ± 0.7 μg C m−3 and accounted for 76% and 18% of the estimated SOC, respectively, while during fall-winter, aromatics-SOC (1.64 ± 1.4 μg C m−3) was dominant with a share of 79% in total estimated SOC. These results indicated that anthropogenic aromatics were dominant SOC precursors in the highly industrialized and urbanized PRD region. During summer, SOC levels estimated by elemental carbon (EC) tracer method were not only consistent with but also correlated well with those by SOA-tracer method. During fall-winter, however, SOC by SOA-tracer method was only about one third of that by EC-tracer method. Their gaps were significantly correlated with the biomass burning tracer levoglucosan, indicating that input from biomass burning emission with very high ratios of OC/EC during fall-winter would result in an overestimate of SOC by EC-tracer method. Therefore cautions should be taken when estimating SOC by EC-tracer method, especially when biomass burning exhibits significant influences.
A series of triangular, shape-persistent arylene-ethynylene macrocycles (AEMs) of related structures were synthesized and studied, with a focus on their mesomorphic behavior in correlation with their chemical structure. Generally, these discotic molecules decorated with flexible side chains demonstrated a propensity to form thermotropic liquid-crystalline (LC) phases. Characterized by differential scanning calorimetry (DSC), polarized optical microscopy (POM), and X-ray diffraction (XRD), four of the eight investigated macrocycles manifested thermodynamically stable mesophases, featuring discotic nematic or columnar structures. Longer alkyl side chains were found more conducive to mesophases, and the alkoxycarbonyl functionality was a more effective side-chain linkage at inducing and stabilizing the LC states than the alkoxy side group. The size and structure of the cyclic aromatic backbone influenced both the occurrence and type of mesophase exhibited.
Using an ultracompact groove-slit-groove (GSG) structure, a refractive index sensor with a broadband response is proposed and experimentally demonstrated. Due to the interference of surface plasmon polaritons (SPPs), the transmission spectra in the GSG structure exhibit oscillation behaviors in a broad bandwidth, and they are quite sensitive to the refractive index of the surroundings. Based on the principle, the characteristics of its refractive index sensing are demonstrated experimentally. In the experiment, the structure is illuminated with a bulk light source (not a tightly focused light source) from the back side. This decreases the difficulty of the experimental measurement and can protect strong light sources from damaging the detection samples. Meanwhile, the whole structure of the sensor can be made more ultracompact without considering the influence of the incident waves.